Wire spuing for cushioned seats



July 19, 1938. M. FREUND WIRE SPRING FOR CUSHIONED SEATS AND BACKS Filed Feb. 5, 1936 PIE-1 F'IE- 4- MDRRJS r'REu vr Patente Juiy i9, 193

WIRE SPRING FOR CUSHIONED SEATS AND BACKS Application February 5, 1936, Serial No. 62,490 2 Claims. (Cl. -179) This invention relates to flat springs of sinuous or similar shape as used for seats, backs of seats, flat cushions and the like. Flat springs offer little resistance to bending stresses and to overcomethis defect it has been proposed to give fiat springs a permanent set on an arc of greater curvature than the springs assume, when in use. The described presetting however is insufficient to fully overcome the above stated defect of fiat springs, particularly, when the springs are under heavier load, and exposes the springs to deforming stresses when under heavier load.

It is the primary object of the present invention to overcome the above described defect of flat springs by providing a fiat spring of the type referred to with means at its opposite ends adapted to effect curving and longitudinal stretching of the spring, when same is attached to the frame of a piece of furniture, such as a chair or daven-- port. I

Another object of the invention is the provision of a flat spring of the type referred to with attachment means secured to the opposite ends of the spring so as to effect upward bulging and longitudinal stretching of the spring over its. en-

tire length, when the spring is attached and secured to the frame of a piece of furniture.

A further object of the invention is the provision of a fiat spring of the type referred to with fiat attachment means having their fiat central areas secured to the opposite ends of the spring at an inclination with respect to the longitudinal axis of the spring, so as to effect an upward bulging and longitudinal stretching of the spring, when the attachment means are forcibly seated upon and secured'to the straight top faces of the rails of a furniture frame.

Still another object of the invention is the provision of a flat spring having its body portion twisted to screw-like shape, with attachment means secured to the opposite ends of the twisted body of the spring at an inclination with respect to the axis thereof, so as to effect upward bulging, longitudinal stretching and axial twisting of the spring body, when the attachment means are forcibly seated upon and secured to the upper faces of the rails of a furniture frame.

In addition the invention has certain other marked superiorities which radically distinguish it from the presently known structures above referred to. These improvements or superiorities embodying certain novel features of construction are clearly set forth in the following specification and the appended claims; and a preferred form of embodiment of the invention is hereinafter shown with reference to the accompanying drawing forming part of the specification.

In the drawing:

Figure 1 shows a top view of a fiat spring of sinuous shape having at its opposite ends flat attachment means secured thereto adapted to rigidly attach the spring to a furniture frame and simultaneously effect upward bulging and longitudinal stretching of the spring.

Figure 2 is a sectional view through a chair having spring structures as shown in Fig. 1 secured to the frame of the chair for supporting the seat thereof.

Figure 3 is an enlarged fragmentary view of the spring shown in Fig. 1, the attachment means being secured, to the fragmentarily disclosed frame of a chair.

Figure 4 shows in full lines a side view of a spring according to the invention resting on the top faces of the rails of a frame prior to the attachment of the spring to the frame and in dashdotted lines the spring after having been attached tothe frame.

Figure 5 is a. plan view of a spring structure similar to that shown in Fig. l with the exception that the body of the spring structure is axially twisted, and

Figure 6 is a perspective view of a spring similar to Fig. 1, with the attachment means being integrally formed at opposite ends of the-spring.

Referring more particularly to the drawing, reference numeral 2 represents a flat sinuous spring, made of steel wire bent to sinuous shape, so that the loops 3 of the spring extend substantially parallel to each other and permit of longitudinal extension and/or compression of the spring under load. The opposite ends of the spring 2 are connected with the central areas of preferably fiat attaching brackets 4, which brackets embody perforations 5 for nailing these brackets to the rails 6 of a frame I by means of nails 8. Each of the brackets 6 has its central area provided with two struck out or ear portions 9 adapted to receive the ends in of the spring 2. Preferably, as shown, the ear portions 9 are made by slitting the bracket on parallel lines, rectangular to the longitudinal axis of the bracket and forcing the portion between the slits upwardly, so as to form substantially half circular bands adapted to slidably hold the ends H] of the spring. It is obvious that brackets l and the spring 2 may be secured to each other in any other practical manner.

The just described connection between the brackets l and the spring 2 is not rigid and perthe ends of the spring when same is secured to the top rail of a frame, the extending end portions ll of the ends ID of the spring 2 are bent at i2 to forth short arms ll arranged at an inclination of approximately to 45 with respect to the plane in which the fiat spring extends. This arrangement secures a non-rotatable connection of the brackets with the spring 2, when the arms I4 engage the brackets, that is when brackets I and the plane of the fiat spring 2 are inclined to each other approximately 30 to 45.

The inclination of the brackets 4 with respect to the plane of the spring 2 effects automatic upward bulging of the spring and stretching of the loops over the entire length, when the brackets are secured to and forcibly seated upon the top faces of the rails 6, as will clearly be understood from an inspection of Fig. 4. In this figure the spring structure is shown prior to its mounting upon the rails of a frame and also after having been mounted on the rails of the frame. In mounting operations of the spring structure upon the rails of the frame the operator places the brackets 4 of the spring structure upon the top faces of the front and rear rails G, then slightly fastens both brackets of the spring structure to the rails by driving nails 8 through the perforations 5 partly into the rails G for preventing axial shifting of the spring structure and finally drives home these nails until the lower faces of the brackets 4 snugly engage the top faces of the rails 6. The last step of the assembly operations induces a slight rotation of the brackets and therewith an upward bulging and stretching of the spring body 2, thus stiffening said body for a more effective yielding counter-action against downward bulging of the spring body under load. Where it is desirable to increase the stiffness ofthe spring body without increasing the wire thickness, I prefer the use of a twisted spring body 2, such as shown in Fig. 5. In this figure the body l5 of the spring structure is axially twisted to screwlike shape so that the brackets 4 are inclined with respect to the axis of the spring body l5 and the axes of the brackets extend in different directions. This spring structure, when secured to the top faces of the front and rear rails of a frame in the manner previously described, embodies an upwardly bulged,, longitudinally stretched and axially twisted spring body, the

twisting of which materially stiffens same due to the horizontal stresses in the spring body. Otherwise the structure is similar to the structure disclosed in Figs. 1 through 4.

The ends I0 of the spring body 2 should extend in opposite directions to insure proper symmetrical distribution of the stresses over the entire spring body and avoid twisting of said body. This construction of the spring body is particularly important, when the brackets 4 are omitted and the body iii of the structure is provided at its opposite ends with short preferably straight attachment extensions I! for attaching the body I6 to therails of a'frame, see Fig. 6. These extensions which are angularly related to the iongitudinal axis of the spring in a plane rectangular to the seating surface of the body I6 are attached to the rails by means of staples or similar connections and will effect an upward bulging and longitudinal stretching of the body [6 similar to that previously described.

When it is desirable to increase or decrease the resistance of the spring body against downward bulging at one or the other end of the spring body, then the inclination of the attachment means with respect to the axis of the spring is changed at that particular end.

Having thus described my invention what I claim is:

1. In a cushioned seat, back or the like, embodying an arched surface, the combination of a frame with a plurality of springs secured to said frame and bridging said frame in arches cross-wise thereof, each of said springs in the untensioned condition embodying a horizontally corrugated, substantially straight seating portion equal in length to the depth of said frame, and attachment means at opposite ends of said seating portion, said attachment means in the un tensioned condition extending upwardly and outwardly at an inclination with respect to the longitudinal axis of said portion and in the as" sembled condition being brought down into the plane of the frame and secured thereto with the ends of said frame spaced apart the same distance as before, whereby to effect longitudinal stretching and upward bulging of the spring.

MORRIS FREUND. 

